Abdulrahman al-AwlakiThe missile strike on Sept. 30, 2011, that killed Mr. Awlaki — a terrorist leader whose death lawyers in the Obama administration believed to be justifiable — also killed Mr. Khan, though officials had judged he was not a significant enough threat to warrant being specifically targeted. The next month, another drone strike mistakenly killed Mr. Awlaki’s 16-year-old son, Abdulrahman, who had set off into the Yemeni desert in search of his father. Within just two weeks, the American government had killed three of its own citizens in Yemen. Only one had been killed on purpose.

Aftermath of US Drone Strike in AfghanistanFacing the possibility that President Obama might not win a second term, his administration accelerated work in the weeks before the election to develop explicit rules for the targeted killing of terrorists by unmanned drones, so that a new president would inherit clear standards and procedures, according to two administration officials.

The matter may have lost some urgency after Nov. 6. But with more than 300 drone strikes and some 2,500 people killed by the Central Intelligence Agency and the military since Mr. Obama first took office, the administration is still pushing to make the rules formal and resolve internal uncertainty and disagreement about exactly when lethal action is justified.

For more than five years, Abu Sufian Ibrahim Ahmed Hamuda bin Qumu (see his Guantanamo detainee file) was a prisoner at the Guantánamo Bay prison, judged “a probable member of Al Qaeda” by the analysts there. They concluded in a newly disclosed 2005 assessment that his release would represent a “medium to high risk, as he is likely to pose a threat to the U.S., its interests and allies.”

Today, Mr. Qumu, 51, is a notable figure in the Libyan rebels’ fight to oust Col. Muammar el-Qaddafi, reportedly a leader of a ragtag band of fighters known as the Darnah Brigade for his birthplace, this shabby port town of 100,000 people in northeast Libya. The former enemy and prisoner of the United States is now an ally of sorts, a remarkable turnabout resulting from shifting American policies rather than any obvious change in Mr. Qumu.